### Conveners

#### Perturbative and non-Perturbative QCD

- Christina Mesropian (The Rockefeller University)
- Sean Fleming (University of Arizona)

#### Perturbative and non-Perturbative QCD

- Sean Fleming (University of Arizona)
- Christina Mesropian (Rockefeller University-Unknown-Unknown)

#### Perturbative and non-Perturbative QCD

- Sean Fleming (University of Arizona)
- Christina Mesropian (Rockefeller University-Unknown-Unknown)

#### Perturbative and non-Perturbative QCD

- Christina Mesropian (Rockefeller University-Unknown-Unknown)
- Sean Fleming (University of Arizona)

#### Perturbative and non-Perturbative QCD

- Sean Fleming (University of Arizona)
- Christina Mesropian (Rockefeller University-Unknown-Unknown)

Dr
Saba Zuberi
(UC Berkeley)

8/9/11, 2:00 PM

Perturbative and non-Perturbative QCD

Parallel contribution

Jets play an important role in a broad range of collider studies and there have been many recent developments in understanding them. Unravelling their structure enhances our ability to interpret data, search for new physics and develop our understanding of Monte Carlos. This talk reviews some theoretical developments in jet physics and their connection to recent experimental results.

David Miller
(SLAC National Accelerator Laboratory)

8/9/11, 2:30 PM

Perturbative and non-Perturbative QCD

Parallel contribution

We present results on the measurement of hadronic jet event shapes and jet substructure in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector. These measurements constitute the first dedicated study of hadronic event shapes at high Q^2 in ATLAS. New results are also presented on the measurement of the substructure of these jets and in commissioning the tools for distinguishing...

Herbert Fried
(Brown University)

8/9/11, 2:50 PM

Perturbative and non-Perturbative QCD

Parallel contribution

A simple and previously overlooked choice of one parameter allows the Schwinger/Symanzik Generating Functional of QCD to be re-written in a manifestly gauge-invariant fashion, without the need of Fadeev-Popov insertions. When combined with Fradkin functional representations for the Green's function, G[A], of a quark in an effective color potential A, and the vacuum loop functional L[A], all...

Dr
Jui-Yu Chiu
(Carnegie Mellon University)

8/9/11, 3:10 PM

Perturbative and non-Perturbative QCD

Parallel contribution

We introduce a systematic approach for the resummation of perturbative series which involve large logarithms not only due to large invariant mass ratios but large rapidities as well. Series of this form can appear in a variety of gauge theory observables. The formalism is utilized to calculate the jet broadening event shape and and transverse momentum ($p_T$) distributions in a systematic...

Lee Sawyer
(College of Engineering and Science-Louisiana Technical Universi)

8/10/11, 2:00 PM

Perturbative and non-Perturbative QCD

Parallel contribution

We present the first measurement of the inclusive three-jet differential
cross section as a function of the invariant mass of the three jets
with the largest transverse momenta in an event in
$p\bar{p}$ collisions at $\sqrt{s}=1.96\, \mathrm{TeV}$.
The measurement is made in different rapidity regions
and for different jet transverse momentum requirements
and is based on a data set...

Dr
Matthew Cleary Tamsett
(College of Engineering and Science-Louisiana Technical Universit)

8/10/11, 2:20 PM

Perturbative and non-Perturbative QCD

Parallel contribution

Inclusive multi-jet production is studied using the ATLAS detector for proton-proton collisions with a center-of-mass energy of 7 TeV. The data sample corresponds to an integrated luminosity of 2.43 pb^-1, using the first proton-proton data collected by the ATLAS detector in 2010. Results on multi-jet cross sections are presented and compared to both leading-order plus parton-shower Monte...

Prof.
Nikolaos Kidonakis
(Kennesaw State University)

8/10/11, 2:40 PM

Perturbative and non-Perturbative QCD

Parallel contribution

I present generalized formulas for approximate corrections to QCD hard-scattering cross sections through second order in the
perturbative expansion. The approximate results are based on recent two-loop calculations for soft and collinear emission near threshold and are illustrated by several applications to strong-interaction processes in hadron colliders.

Ashish Kumar
(Department of Physics-Physics Faculty-State University of New Y)

8/10/11, 3:00 PM

Perturbative and non-Perturbative QCD

Parallel contribution

We present measurements of total and differential cross sections for the production of W or Z bosons in association with jets, including detailed study of the production of heavy flavor jets, using up to 6 fb-1 of ppbar collisions collected with the D0 detector at the Fermilab Tevatron collider. We present measurements of the inclusive W+n jets total cross sections (with n=1-4) and also...

Dr
Costas Vellidis
(Fermilab)

8/11/11, 10:30 AM

Perturbative and non-Perturbative QCD

Parallel contribution

The production of prompt photon pairs with large invariant mass in hadron collisions is a large irreducible background in searches for a low mass Higgs boson decaying into a photon pair, as well as in searches for new phenomena, such as new heavy resonances, extra spatial dimensions or cascade decays of heavy new particles. Precise measurements of the diphoton production differential cross...

Laurent Millischer
(IRFU-CEA - Centre d'Etudes de Saclay (CEA))

8/11/11, 10:50 AM

Perturbative and non-Perturbative QCD

Parallel contribution

Events with two isolated photons are a useful probe of hard-scattering QCD. Also, uncertainty in sigma(diphoton + X) is a major source of systematic error for Higgs and exotic diphoton searches. We present the first measurement of the isolated differential diphoton cross-section from proton-proton collisions at a center-of-mass energy of 7 TeV with the Compact Muon Solenoid detector at CERN....

Mr
Tingjun Yang
(FNAL)

8/11/11, 11:30 AM

Perturbative and non-Perturbative QCD

Parallel contribution

The study of final states with an isolated high energy photon and an identified b-quark jet is a testing ground for QCD predictions at the hadron collider. A cross section measurement provides a probe of the hard scattering dynamics within the proton, and a cross-check of the predictions of its b-quark content, whose parton density function is indirectly extracted from constraints on the gluon...

Dr
Gil Paz
(The University of Chicago)

8/11/11, 11:50 AM

Perturbative and non-Perturbative QCD

Parallel contribution

Recently, the charge radius of the proton was extracted, for the first time, from muonic hydrogen. The value was 5 sigma away from similar measurement of regular hydrogen. The extraction of the charge radius depends on a theoretical input. Together with Richard J. Hill, we are studying the hadronic uncertainty in the theoretical prediction, using the tool of an effective field theory, namely...

Emanuele Mereghetti
(University of Arizona)

8/11/11, 12:10 PM

Perturbative and non-Perturbative QCD

Parallel contribution

We calculate the electric-dipole and magnetic-quadrupole form factors of the deuteron that arise as a low-energy manifestation of parity and time-reversal violation in quark-gluon interactions of effective dimension four and six: the QCD vacuum angle, the quark electric and chromo-electric dipole moments, and the gluon chromo-electric dipole moment. Within the framework of two-flavor chiral...

Dmitry Bandurin
(Kansas State University)

8/12/11, 8:00 AM

Perturbative and non-Perturbative QCD

Parallel contribution

Samples of inclusive $\gamma+{\rm 2~jet}$ and $\gamma+{\rm 3~jet}$ events collected by the D0 experiment
with an integrated luminosity of about 1~fb$^{-1}$ in $p\bar{p}$ collisions
at $\sqrt{s}=1.96$ TeV are used to measure cross sections
as a function of the angle in the plane transverse to the beam direction
between the transverse momentum ($p_T$)
of the $\gamma+$leading jet system...

Dr
Rishiraj Pravahan
(University of Texas at Arlington)

8/12/11, 8:20 AM

Perturbative and non-Perturbative QCD

Parallel contribution

This talk describes minimum bias measurements using proton proton collisions at the ATLAS detector at the LHC at center of mass energies of 900 GeV and 7 TeV. Studies of charged particle multiplicity distributions and multiparticle correlations which are used to investigate soft QCD processes are presented. The measurements are compared with various theoretical models and Monte Carlo generators.

Prof.
Errol Gotsman
(Tel Aviv University)

8/12/11, 8:40 AM

Perturbative and non-Perturbative QCD

Parallel contribution

Monte Carlo generators (Pythia and Phojet) which were tuned for energies up to that of the Tevatron, appear to be found wanting when extended
to LHC energies.
We have constructed a model that satisfies the theoretical
requisites of high energy soft interactions, based on two conjectures:
(i) the results of N =4 SYM, which at present is a unique theory
that allows one to deal with a...

Alessandro Camboni
(Universitat de Barcelona)

8/12/11, 9:00 AM

Perturbative and non-Perturbative QCD

Parallel contribution

LHCb presents studies of particle production in minimum bias events in pp collisions at $\sqrt(s)$=7 TeV.
These studies include measurements of strangeness production, particle ratios, baryon-antibaryon
ratios and charged particle production. The forward coverage and low $p_T$ acceptance of the
experiment makes these measurements very complementary to those performed by the central...

Seth Quackenbush
(Argonne National Laboratory)

8/12/11, 9:20 AM

Perturbative and non-Perturbative QCD

Parallel contribution

We investigate the potential to observe double parton scattering at the LHC in the W b bbar -> e nu b bbar process. Double parton scatterings occur when two partons inside the same hadron each undergo a high scale interaction with two partons of another hadron. The rate for this process is expected to be approximated by the product of the usual single parton distribution functions with...

Andrew Gerhart Brandt
(University of Texas at Arlington)

8/12/11, 9:40 AM

Perturbative and non-Perturbative QCD

Parallel contribution

The elastic proton-antiproton scattering process is studied as a function of
the four-momentum transfer squared $|t|$ at a center-of-mass energy of 1.96 TeV.
Scattered protons and antiprotons are selected by using forward roman pot
detectors that were installed around the D0 interaction point of the Tevatron.
The data presented correspond to a dedicated period of low luminosity running
of...

Dr
Dayong Wang
(Department of Physics-University of Florida)

8/12/11, 4:00 PM

Perturbative and non-Perturbative QCD

Parallel contribution

Studies of hadron production in pp collisions, including charged particle transverse momentum, pseudorapidity and event-by-event multiplicity distributions at sqrt(s) = 0.9, 2.36 and 7 TeV are shown. Measured spectra of identified strange hadrons, reconstructed based on their decay topology, are also presented. Comparisons to several QCD Monte Carlo models and tunes are discussed. Results on...

Hans Jozef H Van Haevermaet
(Universiteit Antwerpen Physics Department)

8/12/11, 4:20 PM

Perturbative and non-Perturbative QCD

Parallel contribution

We present measurements of the forward (3 < |eta| < 5) energy flow in minimum bias events and in events with either hard jets or W and Z bosons produced at central rapidities. Results are compared to MC models with different parameter tunes for the description of the underlying event.